Manufacture of blading for turbines



C. A. PARSONS CARNEGIE, M. BONE, AND S. S. COOK. URE 0F BLADING FORTURBINES. APPLICATION FILED APR=14, I920. RENEWED AUG. 22, 1922. mso oo.

UFACT V MAN I Patented Sept. 26, 1922.

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Patented Sept. 26, 1922,

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I CIHAJRJZIES ALGERNON PARSONS, ALFRED QUINTIINT CARNEGIE, AND MATTHEWBONE,

OF -NEWGASTLE-UPONTYNE, AND STANLEY SMITH COOK, F WALLSEND-UPGN- TYNE,ENGLAND; SAID CARNEGIE, SAID BONE, AND SAID COOK ASSIGNORS T0 SAIDPABSONS.

MANUFACTURE OF ELADING FOR TU MINES.-

Application filed April 14, 1920, Serial No. 373,937. Renewed August 22,1922. Serial No. 883,648.

To all whom it may concern:

Be it known that we, THE HoNoURABLE SIR CHARLES ALGERNQN PARSONS, K. C.B., ALFRED QUINTIN CARNEGIE, and MATTHEW BONE, all subjects of the Kingof Great Britain, and residents of Heaton Works, Newcastle-upon-Tyne, inthe county of Northumberland, England, and STANLEY SMITH Coon, a subjectof the King of Great Britain, and resident of Turbinia Works,VVallsend-upon-Tyne, in the county of Northumberland, England, haveinvented certain new and useful Improvements in the Manufacture ofBlading for Turbines, of which the following is a specification.

l The present invention relates to turbine blading and has for itsobject an improved manner of manufacture whereby theblade propercombined integrally with its base may be readily and cheaply produced.

In the specification of British application No. 16910 of 1918, we havedescribed a method of manufacturing turbine blading in which the base ofthe blade or a mass of, metal from which the'base may be subsequentlymachined is shaped in a die having a suitable aperture, the blade properbeing formed by extrusion through an orifice in the die.

In carrying out this method of manufacture difficulty has beenexperienced owing to the fact that with small billets there is atendency for the edges of the blade, and especially the finer edge, tobe extruded in a jagged condition.

e have found that this objection may be overcome by so shaping theaperture in the die that when the billet of metal is placed therein, itdoes not completely fill the aper- 40 ture in proximity to the orificethrough which the blade is extruded.

The invention, therefore, consists in form- V ing a turbine bladingelement from'a billet in a die, having an aperture in which the base ofthe blade or a mass of metal from which the base can be subsequentlymachined is shaped and an orifice through which the blade proper isextruded, in such a manner that when the operation is carried out an airspace is left in proximity to the lower part of the billet near the edgeof the orifice.

The invention further-consists in forming a die of the type and for thepurpose indicated, having in the aperture which receives the billet ofmetal a recess in close proximity to the extrusion orifice.

The invention also consists in a die of the type and for the purposeindicated, provided in close proximity to the extrusion orifice with arecess wholly or partially surrounding the orifice, of such shape thatwhen the billet is inserted an air space is left in the neighbourhood ofthe lower part of the billet near the edge ofthe orifice.

The invention moreoverconsists in so reducing the section of the billetin proximity to the orifice that an air space is left intheneighbourhood of the lower partof the billet near the edge of theorifice.

The invention further consists in the improved means for manufacturingturbine blades hereinafter described.

stead, however, of forming the sides of the aperture parallel throughouttheir length or converging towards the orifice at the bottom of theaperture, we form some or all of the sides of this aperture so that theydiverge as the bottom of the aperture is approached,

thus making the cross section of the aperture constant throughout aportion of its len th but increased near the bottom.

ysuitably shaping the recess thus formed in the aperture, theparallel-sided billet will not completely fill the increased volume ofthe aperture but will leave an an space therein, and we have found thatby this means an even and continuous, instead of a jagged edge isproduced on the extruded blade.

In the form of the invention illustrated in Figures 1-3, all the sidesof the aperture are made to diverge toward the orifice at" the bottom ofthe aperture, thus leaving a recess t completely surrounding the bil=let 2.

As pointed out above the greatest tendency to unevenness is found on thefiner edge of the blade, and we may therefore merely form a recess inthe side of the aperture adjacent to the end of the orifice throughwhich the finer edge is extruded. Preferably, however, a recess isformed also on the opposite side of the aperture, that is to say,adjacent to both ends of the orifice. This arrangement is illustrated inFigure 4:.

We do not confine ourselves to any particular shape of recess, thisbeing a matter which must be determined by experiment in individualcases. F or example, we may find it advisable so to shape the recessthat its walls converge in a direction away from the orifice and mergegradually into the parallel-sided part of the aperture. Ur

vagain, it may be advantageous to make the walls of the recess parallelleaving a shoulder between them and the parallel-sided part of theaperture in which the billet fits more or less closely before operationof the ram. This latter arrangement is shownin Figure 5, in which therecess 4c, being of the 7 same section throughout its length, is notaperture in the die are formed parallel out so deeply into the die as inthe previous examples.

Tn a further modification, the sides of the throughout their length andthe recess or air space is formed by removing metal from the lower partof the billet so that the sides of the billet are parallel throughout aportion of its length, but some or all of the sides converge towards thebottom.

The metal of the billet when under the heavy pressure necessary toeffect extrusion will enter the recess to more or less degree,

but the entrapped air will serve as an insulater against the loss ofheat so that the anemone and a recess in the aperture, in proximity l tothe extrusion orifice. I

3. A. die of the type and for the purpose indicated, provided in closeproximity to the extrusion orifice with a recess wholly or partiallysurrounding the orifice, .of such a shape that when the billet isinserted, an air space is left in the neighbourhood of the lower part ofthe billet near the edge of the orifice.

4. ln a method of extruding turbine blading, the step of reducing thesection of the billet in proximity to the extrusion orifice so that anair space is left in the neigh borhood of the lower part of the billetnear the edge of the extrusion orifice.

5. A drop forging die provided with an extrusion orifice and a recess inproximity thereto, substantially as described. 7

6. The herein described method of extruding turbine blades, whichconsists in associating a billet and a die seas to provide a spacebetween billet and d1e in roxpressure to the billet.

In testimony whereof we have signed our names to this specification.

CETAKRMZS ALGERNGN PARSQNS.

AXLFKRED @Ulll'lllll CARNEGIE. MATTHEW Blflltli. STANLEY SlllllTl-ll(Ctlltlfi.

so 1 imity to the extrusion orifice, and app ying

